The present invention relates to mower-conditioner platform suspensions and more specifically relates to three-point header suspensions including a single upper arm and integral hydraulic cylinder for lifting the platform.
Mower-conditioner platforms or headers are usually suspended from a support frame so that the platforms float both vertically and laterally, i.e., from side to side, during cutting operation in response to platform skid or gauge shoes encountering irregular terrain or obstacles so that the platforms follow the contour of the terrain to maintain a desired height of cut while avoiding contact of the cutting elements with obstacles.
It is desirable to minimize the cost of platform suspensions while retaining a good floating characteristic. In an attempt to achieve the first objective, designers have created various suspension designs utilizing a single, centrally located upper link and two transversely spaced lower links with a single lift cylinder being connected between the main frame and the upper link. One example of this type of suspension is shown in U.S. Pat. No. 3,241,300 granted to Fell et al on 22 Mar. 1966, and another example is embodied in the Model 904 Mower-Conditioner manufactured by Allis-Chalmers Manufacturing Company and offered for sale in 1969. However, these known designs have the drawback of being somewhat stiff in lateral float due to lack of freedom of motion in the mounting of the upper link.
Such lateral stiffness is overcome by suspension designs embodying a single upper link mounted to the main and platform by ball joint couplings. U.S. Pat. No. 4,187,664 granted to Meek et al on 12 Feb. 1980 discloses such an upper link. A drawback of this upper link is that due to the link being mounted for free side-to-side movement the platform may get into a mode where it undergoes undesirable side-to-side rocking motion during transport.